it depends, if it's a week where i have nothing to do i read everything (or ALMOST, some really long journal entries i skip). also, a lot of journals that have to do with gender issues i don't read because i don't really have anything to say on that, it's not really something i can relate to.
then sometimes i actually have a life and i don't go on oasis for a while, and afterwards i just read what's on recent journal entries and that's it.
...but some much more thoroughly.
I get to most of them; maybe I'll miss a few if I'm away for a bit, but otherwise it's almost all. It doesn't mean I can always formulate a comment, though.
I said 80-90%. Its higher if I have more homework to do XP